Intel Xeon D 1531 's Advantages
Released 5 years and 9 months late
Newer PCIe version (3 vs 2)
Higher base frequency (2.2GHz vs 2GHz)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (35W vs 85W)
Xeon EC5509 's Advantages
Higher specification of memory (1066 vs 4)
Larger L3 cache size (8MB vs 1.5MB)